Photocell



ZEN-[CHI KAMAYACH! ET AL 2,276,198

March 10, 1942.

PHOTOGELL Filed Sept. 12, 1939 6761 I C O/VDUC 771 5 M55444 /C MVEE SELE/V/UM 1-H YER 5 5/755 ELECTRODE 4,975? or MEI-AL FROM 77/5 Fall/2771' PE/F/Ofl/C GROUP ATTORNEY i Patented Mar. 1942 PHOTOCELL Zen-Ichi Kamayaclii and Kenichi Ishii, ,Shibaku,

Tokyo, Japan,

assignors to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware In Japan October 5, 1938 Application September 12, 1939, Serial No. 29;,510

' This invention relates to a photocell which-is formed by applying a selenium semi-conductor.

upon "the surface of a base electrode plate by coating a. thin film of a fourth-group metal such as tin, lead etc. upon the surface thereof and still more by coating a thin film of platinum, silver etc. thereupon. Its object is to obtain a photocell which is excellent in sensitivity.

The drawing is a view showing the construction of a sensitive element in the photocell of this invention.

This invention is related to the improvement of a photocell using a selenium semi-conductor. In a photocell of this type practiced heretofore,

. it is formed by having a selenium semi-conductor applied upon a basemetallic plate and by having a thin film of platinum, silver, copper etc. coated upon the surface thereof. v

1 Claim. (Cl. 136-89) time under pressure, therebyc'onstructing a seleniumsemi-conductor having a thickness unimetal had been attached upon the surface 'of the form in sensitivity.

Reference numeral 3 shows a thin film in which one or several kinds of a fourth-group selenium by a spraying or distillation method.

Reference numeral 4 is a platinum or silver coating. It is necessary that the thin films composed of the layers (3) .(4) are of suitable thickv ness so as" to allow a large amount of light to We produce a photocell by first applying a thin film of a fourth-group metal such as a tin etc.-

upon a selenium semi-conductor which had been applied to a base electrode by a spraying or'distillation method, and then by coating a thin film of platinum, silver etc. upon the surface of said film by a similar method. The photocell thus obtained is striking and excellent in its photoelectric effect.

Reference numeral I shows a base-electrode,

I usually an iron plate thesurface of which is made mechanically coarse. If required, I may be provided with a plating of nickel, cobalt etc.

Reference numeral 2 shows a layer of selenium semi-conductor formed by heating a'base iron plate to a given temperature'for a fixed time prior to its application, by having a molten sele-" nium applied or sprayed thereto and still more by heating it at a normal temperature for a fixed get to the selenium semi-conductor. The sensitive element is then mounted by pressing elec trodes consisting of a copper ring etc. against the upper electrode and the base electrode, re-

spectively. To protect the upper electrode, a glass plate or transparent lacqu'er etc. is provided for the purpose of the mechanical as well as the chemical protection of the sensitive element.

It is 'to be understood of course that although the invention has been described'in and thorium.

What is claimed is A photocell which'comprises a base electrode plate, a coating of aselenium semi-conductor thereon, a thin film of at least one of the metals belonging only to the fourth group of the periodic table of elements on the exposed surface of said selenium. semi-conductor coating, and a transparent film of a substantially chemically inert metal coated on the exposed surface of said thin film.

ZEN-ICI-Il KAMAYACHI.

KENICH rsrm. v

connection with tin and leadas possible fourth group metals for the layer 3, others may beemployed, such as titanium, germanium, zirconium, cerium, silicon, 

